The present invention relates to apparatus for inserting an intraocular lens through a small incision into an eye, to methods for making such apparatus and to methods for inserting an intraocular lens into an eye. More particularly, the invention relates to an apparatus which has enhanced lubricity and is useful for inserting a foldable intraocular lens into an eye, to methods for making such apparatus and to methods using such apparatus to insert a foldable intraocular lens into an eye.
An intraocular lens (IOL) is implanted in the eye, for example, as a replacement for the natural crystalline lens after cataract surgery or to alter the optical properties of (provide vision correction to) an eye in which the natural lens remains. IOLs often include an optic, and preferably at least one flexible fixation member or haptic which extends from the optic and becomes affixed in the eye to secure the lens in position. The optic normally includes an optically clear lens. Implantation of such IOLs into the eye involves making an incision in the eye. It is advantageous, to reduce trauma and speed healing, to have an incision size as small as possible.
IOLs are known which are foldable (deformable) so that the IOL can be inserted through a smaller incision into the eye. A substantial number of instruments have been proposed to aid in inserting such a foldable lens in the eye.
Many of the prior art IOL insertion systems load and/or fold the lens at the distal end, that is at the end closest to the eye or the end inserted into the eye. Such xe2x80x9cdistal loadingxe2x80x9d systems often disadvantageously include a space consuming loading component at or near the distal end of the system which causes the distal end to be relatively large. This relatively large distal end makes inserting the IOL through a small incision more difficult, if not impossible. Systems which fold and load the IOL proximally of the distal end provide certain advantages, such as reduced stress on the IOL and/or inserter, relative to xe2x80x9cdistal loadingxe2x80x9d systems.
However, whether using a distal loading or proximal loading system, one factor which limits the size of the inserter tube involves the inserter tube itself. For example, the material from which the inserter tube is made, for example, polypropylene and the like polymeric materials, may not be compatible or otherwise susceptible to causing optics, for example, made from silicone polymeric materials, to pass through relatively small hollow spaces. For example, the injector tubes may be made of materials, in particular polymeric materials, which have insufficient lubricity to facilitate the passage of a folded IOL through the tube.
As a result of this lack of lubricity, the hollow space of the injector tube must be made relatively larger to accommodate the folded intraocular lens. This is detriment since, as noted above, it is advantageous to have the smallest possible incision for insertion of the IOL. In addition, if one were to use a small diameter tube to pass the IOL, excessive force might be needed to pass the IOL through the small hollow space thereby increasing the risks of damaging the IOL and, in extreme cases, even damaging the eye into which the IOL is placed.
One approach that may be considered is to use a lubricity agent, for example, such as conventional visco-elastic agents, in the hollow space of the tube to facilitate passing the IOL through the insertion apparatus. However, such lubricity agents in and of themselves occupy valuable space, thereby at least partially defeating the purpose of using such agents. Also, such lubricity agents often end up in the eye, thereby creating the risk of causing trauma and/or irritation and/or damage to the eye.
It would be advantageous to provide straightforward IOL insertion apparatus and methods for using same which facilitate the passage of folded IOLs through the apparatus in a controlled manner without using excessive force.
New apparatus for injecting IOLs and methods for making and using such apparatus have been discovered. The present apparatus achieve enhanced lubricity, thus providing for the use of effective, reliable and non-excessive amounts of force to inject a folded IOL into an eye. The present IOL inserter production methods provide inserters which have very effective and reliable lubricity properties. The present invention is easy to practice. The methods of use included in the present invention often involve surgical techniques which are well practiced and conventionally used to insert IOLs into eyes.
In general, the present invention involves apparatus for inserting IOLs into an eye which include a lubricity enhancing component physically secured to the apparatus and concentrated at or near the interior wall or walls of the apparatus, for example, at or near the interior wall of the apparatus defining a hollow space through which an IOL is passed. It has been found that the inclusion of such a physically secured or bonded lubricity enhancing component is effective to facilitate the passage of the IOL through the apparatus. Physically securing or bonding such lubricity enhancing components in or on the apparatus is particularly effective since the amount of such component present, and the degree of enhanced lubricity obtained, is conveniently controlled and stable on a long term basis, for example, the apparatus has a relatively long shelf life before use. Preferably, a reduced amount of the physically secured or bonded lubricity enhancing component passes into the eye during use of the present apparatus relative to a similar or substantially identical apparatus on which the lubricity enhancing component is not bonded or secured to the apparatus.
In one embodiment, the present apparatus include an interior wall which is a plasma-exposed interior wall. This plasma-exposed interior wall preferably has an enhanced ability to physically secure or bond the lubricity enhancing component relative to a substantially identical interior wall which is not plasma-exposed. In one useful embodiment, the plasma-exposed interior wall facilitates forming the lubricity enhancing component concentrated at or near the interior wall of the hollow tube.
In general, the present methods for producing IOL insertion apparatus comprise exposing a hollow tube including a material and having an interior wall defining a hollow space through which an IOL is passed and an outlet though which the IOL is passed from the hollow space into an eye to an effective plasma, and providing an effective amount of a lubricity enhancing component at or near the interior surface. It has been found that the combination of the exposing step and the providing step is effective to facilitate the passage of the IOL through the hollow space.
The use of the present IOL insertion apparatus allows successful injection of silicone-based IOLs, for example, employing inserters made of polypropylene and the like polymeric materials, through incisions of about 3.5 mm or about 3.2 mm or less, preferably about 3.0 mm or less, and still more preferably about 2.8 mm or less.
In one broad aspect of the present invention, apparatus for inserting IOLs through small incisions into eyes are provided. Such apparatus comprise a hollow tube including (or made of) a material, preferably a polymeric material, and having an interior wall defining a hollow space through which an IOL is passed and an outlet, preferably a distal end opening, through which the IOL is passed from the hollow space into an eye. A lubricity enhancing component, preferably selected from hydrophilic components, oleophilic components and mixtures thereof, more preferably selected from oleophilic components, other than the material, is physically secured or bonded to the hollow tube and concentrated at or near the interior wall. The hollow tube, and in particular the interior wall, is preferably exposed to a plasma, more preferably a sub-atmospheric pressure oxygen-containing plasma. The combination of the lubricity enhancing component and exposing the interior wall of the hollow tube to plasma preferably is effective to facilitate the passage of the IOL through the hollow space. The lubricity enhancing component preferably is present in a minor amount, more preferably in the range of about 0.1% to about 1% or about 10% or about 20%, of the total weight of the hollow tube. The lubricity enhancing component is physically secured, for example, physically bonded, admixed or combined, to the other material making up the hollow tube using methods known in the art, such as by blending or mixing the lubricity enhancing component and other material prior to forming the hollow tube and/or forming a coating of lubricity enhancing components on the already formed hollow tube.
By xe2x80x9cphysicallyxe2x80x9d securing or bonding is meant a non-covalent chemical bonding joining or coupling, and preferably a non-chemical bonding, joining or coupling. Some interaction, for example, ionic and/or electrical interactions may occur between the lubricity enhancing component and the other material or materials making up the hollow tube. However, the present xe2x80x9cphysicalxe2x80x9d securing or bonding is clearly distinguished from forming covalent chemical bonds between the lubricity enhancing component and the other material or materials making up the hollow tube. The prior art has suggested providing covalent chemically bonded lubricants to avoid losing the lubricant during use. It has now been found that physically secured or bonded lubricity enhancing components have a reduced tendency to be lost (from the IOL inserter) during use of the present IOL inserters. Thus, physically securing or bonding the lubricity enhancing component to the hollow tube is any suitable coupling or joining which is not covalent chemical bonding of the lubricity enhancing component to the other material of the hollow tube.
In a particularly useful embodiment, the lubricity enhancing component is effective to reduce the force needed to pass the IOL through the hollow space of the tube relative to the force needed to pass an identical IOL through the hollow space of a similar apparatus without the lubricity enhancing component. This xe2x80x9creduced forcexe2x80x9d feature of the present invention is particularly useful, even when no reduction in the size of the incision is obtained. The use of reduced force allows the surgeon to have more control of the rate at which the IOL is inserted into the eye and, in addition, reduces the risk of damage to the eye during IOL insertion.
The material from which the hollow tube preferably is made is a polymeric material, for example, a hydrophobic polymeric material, more preferably selected from polyolefins, such as polypropylene and the like materials.
In one useful embodiment, the present apparatus further comprises a loading portion including a material and having an internal wall defining a chamber sized and adapted to receive an IOL for passage into the hollow space. A further lubricity enhancing component, preferably another amount of the same lubricity enhancing component employed in the hollow tube, preferably is physically secured to the loading portion and concentrated at or near the internal wall of the loading portion. This further lubricity enhancing component is effective to facilitate the passage of an IOL into the hollow space. The internal wall of the loading portion preferably is exposed to a further plasma, preferably the same plasma used with the hollow tube. In one embodiment, the combination of the further lubricity enhancing component and the further plasma is effective to further facilitate the passage of the IOL into the hollow space. Both the interior wall of the hollow tube and the internal wall of the loading portion preferably include effective amounts of the lubricity enhancing component and are exposed to plasma to facilitate passage of the IOL from the loading portion into the hollow tube and from the hollow tube into the eye. In addition, it is often more convenient to treat both the hollow tube and loading portion, which together preferably are a single, integrally formed unit, with the lubricity enhancing component and plasma, rather than treating only the hollow tube.
The loading portion preferably is sized and adapted to receive an IOL, for example, in an unfolded state, and to hold the IOL in a folded state. The loading portion can be structured to at least facilitate the folding of the IOL from the unfolded state to a folded state. The hollow tube includes an interior wall which defines a hollow space preferably sized to receive the IOL in a folded state from the loading portion and to pass the folded IOL to an open outlet through which the IOL is passed into an eye.
Methods for producing apparatus for inserting an IOL through a small incision in the eye are provided and are included within the scope of the present invention. These methods have, in general, been discussed above, and comprise exposing a hollow tube to plasma and providing an effective amount of a lubricity enhancing component physically secured to said hollow tube and concentrated at or near the interior wall of the hollow tube. More specifically, the plasma employed is preferably a sub-atmospheric pressure plasma, more preferably a sub-atmospheric pressure, oxygen-containing plasma, although other plasmas are suitable.
As used herein, the term xe2x80x9cconcentratedxe2x80x9d means that the lubricity enhancing component is located in a higher concentration at or near one or more portions, for example, the surfaces, of an article than at one or more other portions, for example, the interior, of the article. This includes the situation in which the lubricity enhancing component is located as a coating on the interior surface of the hollow tube and is not present in the hollow tube itself. Also included is a situation in which the hollow tube includes a concentration of lubricity enhancing component throughout with a locally higher concentration present at or near the interior surface of the hollow tube.
In one embodiment, the lubricity enhancing component is physically secured or bonded to the hollow tube prior to the exposing step. In a particularly useful embodiment, the providing step includes subjecting the hollow tube having an amount of lubricity enhancing component spaced apart from the interior wall to conditions effective to cause this amount of lubricity enhancing component to form at least a portion of the effective amount of the lubricity enhancing component at or near the interior wall. For example, the hollow tube can be subjected to elevated temperatures for substantial periods of time, such as on the order of about 6 hours or about 12 hours to about 100 hours or more, to cause the lubricity enhancing component to move toward the surface. This xe2x80x9cbloomingxe2x80x9d action is very effective in providing the desired amount of lubricity enhancing component concentrated at or near the interior wall of the hollow tube.
In addition, the loading portion can be formed by comparable exposing and providing steps.
Methods for inserting an IOL into an eye are also provided and are included within the scope of the present invention. In one embodiment, such methods comprise placing an outlet or distal end opening of the hollow tube of the present apparatus in or in proximity to an incision in an eye, and passing at IOL from the hollow tube through the outlet or opening into the eye.
These and other aspects of the present invention will become apparent in the following detailed description and claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numerals.